Fan assembly

ABSTRACT

A fan assembly generally comprising at least one fan blade unit of at least two curved fan blades centrally attached to a hollow rotational shaft through which air flows into the fan blade and exits on the leeward edge of the fan blade tip;

DOMESTIC PRIORITY

This application claims the benefit of the filing date for ProvisionalApplication No. 61/268,165, filed Jun. 9, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a solar powered fan assembly.

2. Description of the Prior Art

Most home owners especially those in the Southwestern United States,have somewhere located on the roof of their house an exhaust fandesigned to move hot air from the attic space to the outside. Theseexhaust fans are commonly referred to as turbine fans because of thearrangement of the blades and work on the simple principle that hot airrises. As the air inside an attic heats up, it rises creating a currentwhich causes the fan blades to rotate.

It is commonly known in the art that a temperature differential acrossthe external structure of a fan can be used to turn the blades of suchfan. For instance, U.S. Pat. No. 5,381,048, issued to William Baird forSolar Venturi Turbine; U.S. Pat. No., 3,757,146, issued to Wesley Love,for Thermoelectric Generator; and, US Patent Publication No.2008/0087315, to Glenn Deming for Thermoelectric Fan for Radiation BasedHeaters, and Methods Related Thereto; all disclose a fan that produceselectrical energy based upon a temperature gradient. Additionally, U.S.Pat. No. 6,707,669, to Jen Lee, for Heat Dissipation Apparatus; U.S.Pat. No. 5,544,488 to Randall Reid for Sel Powered Heat Transfer Fan;and US Patent Publication 2008/0134690 to Randall Reid for Self PoweredHeat Transfer Fan, disclose fans which do not produce electrical energybut which are powered completely by temperature differentials.

What is not shown in the prior art is a fan assembly in which therotational force by which the fan turns is created by virtue of hot airrising through the internal structure of such fan.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a fanassembly which allows air flow through the internal structure of suchfan to create the rotational force necessary to cause the fan to turn.Other objects and advantages of the present invention will becomeapparent from the following detailed description when viewed inconjunction with the accompanying drawings, which set forth certainembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the fan assembly of the present invention.

FIG. 2 is a top view of the fan assembly of the present invention.

FIG. 3 is a close up side view of a single fan blade.

FIG. 4 is a close up top view of a single fan blade.

FIG. 5 is an illustration of the fan assembly of the present inventionin operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed embodiments of the present invention are disclosed herein.It should be understood, however, that the disclosed embodiments aremerely exemplary of the invention, which may be embodied in variousforms. Therefore, the details disclosed herein are not to be interpretedas limiting, but merely as the basis for the claims and as a basis forteaching one skilled in the art how to make and/or use the invention.

As depicted in FIG. 1, the fan assembly of the present inventioncomprises a series of fan blade units [2] centrally attached to a hollowrotational shaft [1] having a closed bottom [8] and top [9]. The bottom[8] and top [9] of the rotational shaft [1] can be attached to therespective surfaces of a typical attic fan or skylight using anyconventional means so long as the rotational shaft [1] can freely turn.At the bottom [8] of the rotational shaft [1] are air entry ports [3]which allow air to enter the shaft [1]. Although any number of air entryports [3] may be used so long as each port has a corresponding oppositeport, the current invention utilizes two of such ports. While three fanblade units [2] are shown in FIG. 1, only one fan blade unit [2], thatbeing the fan blade unit located at the top of the hollow rotationalshaft [1], the moving unit [15], is necessary for the operation of thepresent invention.

FIGS. 2, 3 and 4 illustrate the moving unit [15] of the presentinvention. Although four fan blades [10] of particular geometry areshown in FIG. 2, any number or shape of vanes may be use so long as theblades [10] remain balanced upon the rotational shaft [1]. As shown inFIG. 3, the upper [4] and bottom [5] surfaces of the fan blades [10] ofthe moving unit [15] are curved in such a manner as to allow a space [6]between the two. To allow sunlight to shine through the upper [4] curvedsurface of the fan blades [10] of the moving unit [15], such surface ismade from clear plastic, although any surface which is transparent willsuffice. The bottom [5] curved surface of the fan blade [10] of themoving unit [15] is made from any opaque material of sufficient strengthand rigidity as to support the fan blade [10]. To further increase airflow by increasing the temperature differential, FIG. 3 shows thatwithin the space [6] between the two curved surfaces [4 and 5], a strip[7] of lightweight heat absorbing material may be placed. There are manytypes of material that will absorb heat currently available whichinclude chemical compounds, chemical liquids, most types of metal, sandand rock. In the present invention, a strip of copper has been found toabsorb heat adequately without detrimentally effecting the weight of thefan blade [2]. While not necessary for the operation of the fan assemblyof the present invention, instead of a heat absorption strip [7] or inaddition to, FIGS. 3 and 4 depict the placement of water filled tubes[12] which function, in addition to increasing heat differential, todeflect the flow or air towards the fan blade exit ports [13].

As shown in FIG. 1, air enters the bottom of the rotational shaft [1]through the air entry ports [3]. As the hot air rises it will reach themoving unit [15]. FIG. 4 illustrates that each of the four (4) fanblades [10] of the moving unit [15] are connected to the rotationalshaft [1] in such a way as to allow air from the shaft to enter the fanblade [10]. While the size and geometry of the fan blade air entry port[11] is not critical, in the present invention, the fan blade air entryport is simply a hole. As depicted in FIGS. 3, 4 and 5, sunlightpenetrating the upper curved surface [4] of the fan blade [10] willcause the air, the water filled tube [12], and the heat absorbing strip[7] to heat increasing the temperature and pressure differential acrosssuch blade. As shown in FIG. 3, the fan blade exit ports [13] arelocated at the leeward edge of the fan blade [10] tip. The hot airexiting through the fan blade air exit ports [13] will creating arotational force which will cause the fan assembly to turn. The otherfan blade units [2] depicted in FIG. 1 are not open to the hollowrotational shaft [1] and act only to assist in the rotation of thehollow rotational shaft [1].

The fan assembly of the present invention can be used in many differentapplications such as to replace existing attic fans. Furthermore, thefan of the current invention could be placed within a skylight.

While the preferred embodiments have been shown and described, it willbe understood that there is no intent to limit the invention by suchdisclosure, but rather, is intended to cover all modifications andalternate constructions falling within the spirit and scope of theinvention as defined in the appended claims.

1. A fan assembly comprising: at least one fan blade unit comprising atleast two fan blades centrally attached to a hollow rotational shaftsealed at the top and bottom wherein the fan blades to said fan bladeunit further comprise an upper curved surface of transparent material, abottom curved surface of opaque material, a space between the two curvedsurfaces, an air inlet at the edge of the fan blade attached to thehollow rotational shaft and an air exit on the leeward edge of said fanblade tip; at least two air inlets located opposite to each other at thebottom of the hollow rotational shaft on the horizontal surface of saidshaft.
 2. The fan assembly of claim 1 further comprising a heatabsorption strip within the space between the upper and bottom curvedsurfaces.
 3. The fan assembly of claim 1 further comprising a waterfilled tube within the space between the upper and bottom curvedsurfaces.
 4. The fan assembly of claim 2 wherein the heat absorptionstrip within the space between the upper and bottom curved surfaces ismade of copper.
 5. The fan assembly of claim 1 wherein there are fourfan blades.
 6. A fan assembly comprising: at least one fan blade unitcomprising at least two fan blades centrally attached to the top of ahollow rotational shaft sealed at the top and bottom wherein the fanblades to said fan blade unit further comprise an upper curved surfaceof transparent material, a bottom curved surface of opaque material, aspace between the two curved surfaces, an air inlet at the edge of thefan blade attached to the hollow rotational shaft and an air exit on theleeward edge of said fan blade tip; at least one fan blade unitcomprising at least two fan blades centrally attached below the fanblade unit attached to the top of a hollow rotational shaft sealed atthe top and bottom wherein the fan blades to said fan blade unit furthercomprise an upper and bottom curved surface and which are not open toair flow from the hollow rotational shaft; at least two air inletslocated opposite to each other at the bottom of the hollow rotationalshaft on the horizontal surface of said shaft.
 7. The fan assembly ofclaim 6 further comprising a heat absorption strip within the spacebetween the upper and bottom curved surfaces.
 8. The fan assembly ofclaim 6 further comprising a water filled tube within the space betweenthe upper and bottom curved surfaces.
 9. The fan assembly of claim 7wherein the heat absorption strip within the space between the upper andbottom curved surfaces is made of copper.
 10. The fan assembly of claim6 wherein there are four fan blades.